Fifty four NIH-funded investigators (13 major users, 41 minor users) at the Boston University School of Medicine/Boston Medical Center Campus (BUSM/BMC) require flow cytometry for their NIH-funded studies. These investigators represent most of the departments and divisions within the medical center including, but not limited to the Immunology Training Program, the Cancer Center, the Pulmonary Division, the Amyloid Treatment and Research Program, the Women's Health Interdisciplinary Research Center, and 12 departments in the Schools of Medicine, Public Health, and Dentistry. However, relatively limited flow cytometry resources are available to these investigators. There are three 1980s era BD FACScans and one operator-assisted MoFlo cell sorter on the BUSM/BMC campus. The ageing FACScans are significantly outdated and are insufficient for many of the more advanced studies which exploit emerging technologies and staining reagents. All the instruments are at or beyond full capacity even as the demand for this technology grows. BU investigators have little if any access to the more sophisticated equipment available at other research facilities in the Boston area. Research that is highly relevant to public health (e.g., treatments for cancer, autoimmunity, and infectious disease; environmental causes of cancer) is severely compromised by this lack of appropriate instrumentation. Funds are requested for the purchase of a Becton Dickinson LSR II high performance flow cytometer with solid state lasers for 11 color (upgradable to 18 color) detection, automatic compensation, a high sampling rate, advanced signal detection and data processing, and a 96-well high throughput sample loader. The LSR II would dramatically improve cell analysis capabilities and would draw other members of the BUSM/BMC community into collaborative studies requiring this essential technology. Specific applications would include: detection of rare lymphocyte subsets and accurate assessment of kinase activity, cell activation, proliferation, apoptosis, cytokine production, and Ca2+ flux within specific cell subpopulations. Significant expertise is present at BU to perform these studies. In conjunction with emerging technologies, the LSR II would dramatically enhance the efficiency, quality, and capability of data acquisition for investigators at this institution while reducing costs. In recognition of these goals, BUSM/BMC is committed to substantial ongoing financial support of this instrumentation and its applications. [unreadable] [unreadable] [unreadable]